Modern offices house an extensive array of electronic and electrical equipment which require both power supply and interconnecting communications cabling. As a result, such buildings commonly incorporate a hollow raised floor which provides cavities/ducts along which the cabling travels. The transition of power, phone lines, data cables and the like from the sub floor cavities/ducts is achieved through recessed compartments commonly known as floor boxes. An example can be seen in PCT/GB92/011011 (AU 19759/92). Floor boxes generally incorporate a frame which extends around an aperture in the barrier. For floors the frame is typically clamped between the floor surface and the underside of the floor deck which may be made of particle board, metal, cementitious materials or a combination thereof. The floor box includes a lid for closing the panel and is adapted to support a service outlet box mounted under the lid. The outlet box will provide an array of sockets connected to the various cable networks. Equipment above the floor is connected via cable leads which pass through one or more hatches in the lid, which is, or are, able to be rotated to either an open position or a closed position. However, such existing devices suffer from a number of substantial deficiencies.
First, conventional recessed floor boxes have a substantial edge surround or carpet frame which overlies the floor finish and usually projects above the floor surface. Common surface finishes in office include loose laid carpet or vinyl tiles, carpet or vinyl sheet and melamine laminate sheet. As used herein the term floor surface or floor surface covering means the upper part of the floor covering, for example, the upper surface of a vinyl tile or the top of the pile of a carpet. Thus, the edge surrounds of conventional recessed floor boxes form a ridge in the floor which is both unsightly and a safety hazard and may for example, cause office workers to trip, or upset trolleys.
Conventional carpet frames are generally made from injection moulded plastic and consequently are not particularly strong. The floor boxes do not meet the building standards set for supporting loads which the floor has to meet. Floor boxes are generally exempted from having to meet those standards because they are not, in theory, subject to the same forces as a floor is typically subjected to particularly point or static loads. However, they may be subjected to rolling loads and it would be advantageous to provide an access panel which was substantially as strong as the floor in which it was located.
A further problem with existing floor boxes occurs in the event of a fire. As discussed, the frames are made of a plastics material and support a relatively heavy outlet box. With the heat caused by fire, there is a tendency for the frame to soften and weaken and the outlet box will fall. This creates an aperture in the floor which acts a chimney and facilitates the spread of fire. Thus the performance of conventional recessed floor boxes, under fire conditions is unsatisfactory.
A further problem with conventional floor boxes is that the lid is unsafe because the lids are not locked down and can be accidentally lifted, for example by pulling the cables. This allows the cables to slip away from the latch opening and under the lid itself, where they are subject to shearing between the lid and the edge of the frame if, for instance, a person stepped on the lid. This not only damages the cables but can be dangerous to staff particularly if the cables are electrical supply cables. A further hazard which can occur if the lid is dislodged, is that the box can trip people. Floor boxes are often inactive in which case they often contain coiled cables. Those coiled cables can expand and push against the lid opening the lid. It is thus desirable that the lid should be latchable when it is both opened and closed.